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We still blind ourselves with science. Take cancer screening: people think the improved technology that allows us to spot lung, prostate or breast cancer earlier helps doctors save lives are saved. It doesn’t.

Mammography of 1,000 women will, on average, mean that four, not five, will die from breast cancer. But deaths from diseases other than breast cancer remain the same, or even rise slightly from 39 to 40. If that small rise is real, “women would simply be trading one type of death for another, at the cost of serious morbidity, anxiety and expense”, say the authors of an article published in the BMJ this month.

They argue that 600,000 women have been through the process and “there is no clear evidence of a reduction in overall mortality with mammography screening”. That’s why the Swiss government’s medical board has decided not to recommend mammograms: the downsides are not compensated for by the lives saved from breast cancer.

We have fooled ourselves into thinking that being able to see the future is the same as being able to change it. At times the opposite is true. Men diagnosed with prostate cancer are more likely to have a heart attack or commit suicide in the year after diagnosis. A lung cancer diagnosis increases the risk of heart attack, stroke and lung collapse.

It’s a lesson we need to apply to the latest source of wide-eyed scientific excitement: the Anthropocene. Geologists have collated evidence that suggests human beings are making a traceable impact on the geological record. At first glance, it’s remarkable. We are the first biological species whose activities have changed the very rock on which we stand. There’s a temptation to see this as evidence of a power and ingenuity that will ultimately make the world a better place. But being able to see the signature of our impact on Earth is no more to be celebrated than the discovery of a cancerous growth.

The most prominent mark is the signature of atomic weapons testing. In the middle of the 20th century, bomb testing created a spike in the level of radioactive particles in the atmosphere. These particles have subsequently been captured in rocks and ice. It would be nice to believe the signature is a spike – not a plateau – because we quickly realised the madness of stockpiling nuclear weapons. We have since learned to perform computer simulations that eliminate the need for much real-world testing, but weapons development, refurbishment and improvement goes on.

According to the Doomsday Clock, a measure of human prospects created by scientists concerned about threats to our existence, it is now just three minutes to midnight. And that was before North Korea tested its latest atomic weapon.

Another signature of the Anthropocene is the fly ash produced by burning fossil fuels. We already know this activity is constraining growing humanity’s ability to find places to live on the planet, and yet a glance at energy policies around the world tells us significant change is not on anyone’s immediate agenda.

Our screening of the Earth shows the signature of the two things most likely to wipe us out. The great lesson from the Anthropocene diagnosis is not that we are impressive, but that humanity’s condition could be terminal. The polio vaccine pioneer Jonas Salk once said our greatest responsibility was to be good ancestors. Sadly, that seems ambitious when it’s not clear we’re going to be ancestors at all.